Auxiliary compound angle grinder for surface grinding machines



March 1960 G. BANKQ 2,926,461

AUXILIARY COMPOUND ANGLE GRINDER FOR SURFACE GRINDING MACHINES FiledSept. 8, 19.58 4 Sheets-Sheet l INVE R. 650265 o ATTOEN March 1, 1960 G.BANKO 2,926,461

AUXILIARY COMPOUND ANGLE GRINDER FOR SURFACE GRINDING MACHINES FiledSept. 8, 1958 4 Sheets-Sheet 2 FLE-EJ IN VENTOR.

I 660265 BAN/ 0 G. BANKO March 1, 1960 AUXILIARY COMPOUND ANGLE GRINDERFOR SURFACE GRINDING MACHINES Filed Sept. 8. 1958 4 Sheets-Sheet 3 March1, 1960 G. BANKO 2,926,461

AUXILIARY COMPOUND ANGLE GRINDER FOR SURFACE GRINDING MACHINES FiledSept. 8. 1958 FIE E 4 Sheets-Sheet 4 ||||H NHL.

Fis 7 INVENTOR. Geo/26.:- BAN/ 0 ATTOEA/EI.

v This invention relates to grinding machines andparticularly toacompound angle grinding attachment for surface grinding machines.

This invention relates'to an improvement in the "device described andclaimed in my U.S. Patent No. 2,821,815,

issued February 4, 1958, and entitled, Auxiliary Compound Angle GrinderFor Surface Grinding Machines. The primary object of this invention isto, provide .means for substantially increasing the length of thegrinding stroke of said attachment without change in the width of theslide.

Another object is to provide "a structure of the type stated, formounting on a conventional surface grinder spindle housing, whosesub-table reciprocating driveshaft remains stationary at all times withreference to'the surface grinder spindle.

A further object is to .provide a resilient belt drive between thesurface grinder spindle and the auxiliary reciprocating spindle. I

Still another object is to provide micro-adjustabilit y for the lengthof stroke of the reciprocating sub table spindle.

These and other objects of the invention will'become apparent from areading of the following specification and claims, together with theaccompanying drawings, wherein:

Figure l is a perspective view'of the auxiliary compound angle grinderthat is the subjectof this invention, showing it mounted on the spindleof a conventional surface grinder;

Figure 2 is a longitudinal sectional view of theattachment showing therelation of the various interconnected rotating and reciprocatingelements;

Figure 3 is a vertical sectional view taken along the the line and inthe direction 'of'the'arrows 33- ofFigure 2;

Figure 4 is a top plan view of the device;

Figure 5 is a' horizontal sectional View taken along the line and in thedirection'of the arrow 5-5 of Figure'2;

Figure 6 is a vertical sectional viewtaken along the the line and in thedirection of the arrows 66 of Figure 2; and

Figure 7 is a perspective view of the unmounted first crank arm, showingthe dovetail ,slot thereof.

Referring more particularly to the drawings there is seen in Figure 1the auxiliary compound angle grinder that is the subject of thisinvention,broadly indicated by reference numeral 10, as it appearsmounted on the spindle housing 67 of a conventionalsurface grinder 30,outlined in broken-lines. r

The surface grinder, broadly indicated by reference numeral 3%) is ofthe usual type having a reciprocating table 32 upon which is supportedavise 33 in which the work piece 34 is held. An upright post or column31 supports the usual motor driven grinding wheel spindle 29 in itshousing 67.

The auxiliary compound angle grinder 1i is'comp'osed Fatented .Mar 1.,.1966

a .of -threemajor parts, namely, .a bracket 11,;a..stat'ionary table 15and a reciprocating sub-table 49. The bracket 11 .is mounteddirectlyoverthe spindle housing 67 of the surface ,grinder v30 .by means of asplit collar 12 which .isc'ompressed around thespindle housing .67 bymeans of abolt 14, as is seen most clearly in Figures 2 and 4. v Apointer 35 .is mountedon the post '31.at thecenter line of the spindle29. This serves as a vertical pointer ..for the angle scale 13 whichextends upwardly of the bracket collar 12 for a purposeto be disclosedhereinafter. vTwo varcuateslots 16 and 17 are .locatedon the "bracket oneither side of the collar .12. The bracket 11 .has the shape of asegmentof a circle with sideedges .68and 69 at 136 to one another. vApivotpoint lug-21is located at the apex of the bracket .11, where'the twosides 68 and 69 meet.

Referencenumeral 15 indicates-a rectangularly shaped stationary tablewhich has a laterally extending lug 20 which is bored to receive abolt-.22. .The table 15 is .mounted on the underside of the bracket llbymeans of abolt 22 which passes through lugs 12%} and-21 and acts as apointaround which the table 15 may bepivoted relative to the bracket 11.The table 15 is also clamped to thebracket by means of boltslS and 19respectively,

-as.is seen in Figures .2 and 4.

The table 15 has wedge-shaped parallel tracks 23 and 24 on the lowerface thereof defining arectangular cavity 47 therebetween, as seen inFigure 6.

-A sub-table 49 is :slidablymounted on the underside of table 15 bymeans of ways or tracks 50 and 51 which mate with the tracks 24 and 23,respectively of table 15.

An auxiliary spindle 62 is journalled on the sub-table 49 cross-wisethereof and parallel to the axis of the surface grinder spindle 29, asseen in Figures 1, 2 and "6.

A double sheave pulley 63 is mounted on the spindle 62 behind thegrinding wheel 64.

Reference numeral 36 indicates a worm housing mounted on the top of thestationary table 15. A wormshaft 37 including a worm 33 is journaled inthe housing 36 cross-wise of the table 15 and parallel to the spindle29.

A crank shaft 40 is journaled in the housing 36'perpendicular to thetable 15 and extending therethrough below the lower face thereof. A wormgear 41 engaged with the worm 38 is mounted on the shaft 40. The gear 41is releasably secured to the crank shaft "49 through a clutch nut 43.

A first crank arm 44 is mounted on the lower end of the crank shaft 40beneath the lower face of the stationary table 15. The crank arm 44 is,cylindrical in shape and :has a diametrical dovetail slot-45 cut in thebottom face thereof. as is seen most clearly in Figure 7. V

A pivot block 25 is slidably mounted in the slot 45. Reference numeral27 indicates a pivot pin mounted on the block 25. Reference numeral 46indicates an adjust; ment screw mounted in the crank arm and threadedlyengaged with the pivot block 25. Rotation of the screw 46 in eitherdirection acts to move the pivot block 25 longitudinally of the slot 45toward or away from the center of rotation of the cylindrical crank arm44-.

By providing a-screw- 46 with a fine thread, such as 40 to the inch, avery fine adjustment of the block is possible. A setscrew 26 can bebrought to bear against the side edge of the block 25 to lock sameagainst movement at the desired position. i

A second crank arm 53'is pivotally mounted on pin 54;, in spacedrelation to the first crank arm 44, on the under side of the table 15,,as seen most clearly in Figures land 4. V

'The second crank arm 53 has a first 'stud 55 positioned proximate itspivot point 54, and second-stud dfi' posi tioned at the free endthereof.

A first connecting rod 57 the pivot pin 27 of the first crank arm 44 andthe stud 55.

A second connecting rod 58 is pivotally mounted between the stud 56 ofthe second crank arm 53 and a pivot pin 59 mounted on the sub-table 49is seen in Figures 2 and 4.

When the crank arm 44 is rotated, this double crank construction causesa relatively large movement of the second connecting rod 58 by a smallmovement of the first connecting rod 57. Thus twice the longitudinalmovement of the table 49 can be effected with this construction withoutincreasing the width of the slides beyond that used with the singlecrank construction described in my Patent No. 2,821,815.

A three sheaved pulley 60 is mounted on the surface grinder spindle 29.

One of the sheaves 61 is aligned with the worm pulley 39, while twosheaves 65 are aligned with the sheaves of the auxiliary pulley 63mounted on the spindle 62.

Reference numerals 66 and 70 indicate driving belts connecting thepulley 60 and the worm pulley 39 and the grinding wheel spindle pulley63, respectively.

These belts are made of material having an inherent natural rubber-likeresiliency so that they can stretch and contract to hold the sametension as the centers of the various spindles move toward or away fromone another as thesub-table 49 reciprocates as described hereinafter.

It will be evident that the auxiliary compound angle grinder 10, justdescribed is an entirely self contained attachment that may be easilymounted or removed from an existing surface grinding machine in a matterof minutes.

. To set up the auxiliary grinder to cut a compound angle, the followingprocedure is used.

The collar 12 is loosened and the whole assembly 10 is swung around thesurface grinder spindle housing 67 within an arc of plus or minus 15degrees with reference to the vertical pointer 35, as indicated on theangle scale 13. The collar 12 is then locked at the desired setting bymeans of the bolt 14. This tilts the table 15 at an angle to thevertical.

The table 15 may then be pivoted laterally plus or minus 10 degrees byloosening the bolts 18, 19 and 22. The table 15 is then pivoted aroundthe bolt 22 to either plus or minus 10 degrees as indicated by the scale28 scribed on the top of table 15, as is seen most clearly in Figure 4.After the required setting is obtained, the bolts 18, 19 and 22 aredrawn up thereby locking the table in angular disposition with referenceto the bracket :11.

The spindle 29 is then started and the power transferred through belts66 and 70 to the sub-table reciprocating mechanism and the auxiliarygrinding wheel spindle 62 of the sub-table, respectively.

The length ofthe stroke of the table 49 is determined 2 by the positionof the pivot block 25 with reference to the center of rotation of thefirst crank arm 44.

This is controlled within close limits by the adjustment screw 46 asdescribed hereinabove.

The pivotal engagement of the first connecting rod 57 with the secondcrank arm 53 at a point 55 proximate its pivot pin 54 while the secondconnecting rod 58 is pivotally mounted on a stud 56 positioned at theextreme free end of the arm 53, provides a multiplying factor in thehorizontal movement of the second connecting rod 58 for every unit oflinear movement of the first connecting rod 57.

Thus double, or better, horizontal movement of the reciprocatingsub-table 49 can be obtained without increasing the width of the tablesbeyond that of those defined in my above identified patent.

The work piece 34 is held stationary and the grinding wheel 64 iscarried across the work face by the reciprocating table 49 which holdsthe grinding wheel 64 at the desired compound angle to the work piece34.

As the grinding progresses, the work piece 34 i f d is pivotally mountedbetween ward toward the grinding wheel 64 to effect the depth of cutdesired.

When the wheel 64 is to be dressed, the worm gear 41 is disconnectedfrom the crank shaft 40 by loosening the clutch nut 43. The sub-table 49will then be held stationary while the grinding wheel 64 rotates. Bypositioning the worm drive shaft 37 on the stationary table 15 thedistance between driving spindle 29 and the driven shaft 37 remainsconstant so that there is no problem-of maintaining constant unvariedpower transmission, as the subtable 49 reciprocates.

At the same time the inherent resiliency of the neoprene" belts 70compensates for the varying center distances between spindles 29 and 62as the table 49 reciprocates.

It will now be clear that there is provided a device which accomplishesthe objectives heretofore set forth. While the invention has beendisclosed in its preferred form, it is to be understood that thespecific embodiment thereof as described and illustrated herein is notto be considered in a limited sense as there may be other forms ormodifications of the invention which should also be construed to comewithin the scope of the appended claims.

I claim:

1. In combination with a surface grinding machine of the type having agrinding wheel spindle housing and a motor driven grinder spindlemounted therein, an auxiliary compound angle grinder, comprising, abracket adapted to be mounted on the grinder spindle housing, includinga stationary table, means for holding said stationary table in adjustedangular positions, both vertically and laterally with reference to theaxial plane of the grinder spindle, a sub-table slidably mounted on theunder side of said stationary table, an auxiliary spindle journaled onsaid sub-table and including a pulley and grinding wheel, a worm housingmounted on the stationary table, a worm shaft journaled therein andincluding a pulley, a pulley mounted on the grinder spindle having afirst sheave aligned with the sub-table spindle pulley and a secondsheave aligned with the worm shaft pulley, a separate resilient drivingbelt connecting each of the paired and aligned pulleys and sheaves, acrank shaft journaled in the stationary table perpendicular to the lowerface thereof and including a worm gear engaged with the worm shaft, acrank arm mounted on said crank shaft below the stationary table androtatable with the crank shaft, and a connecting rod pivotally connectedat one end to the subtable and at the other end torthe crank arm, saidconnecting rod acting to reciprocate the sub-table longitudinally of thestationary table upon rotation of the crank arm.

2. In combination with a surface grinding machine of the type having agrinding wheel spindle housing and a motor driven grinder spindlemounted therein, an auxiliary compound grinder, comprising, a bracketadapted to be mounted on the grinder spindle housing and including astationary table, means for holding said stationary table in adjustedangular positions, both vertically and laterally with reference to theaxial plane of the grinder spindle, a sub-table slidably mounted on theunder side of said stationary table, an auxiliary spindle journaled onsaid subtable, including a pulley and grinding wheel, a worm housingmounted on the stationary table, a worm shaft journaled therein andincluding a pulley, a pulley mounted on the grinder spindle having afirst sheave aligned with the subtable spindle pulley and a secondsheave aligned with the worm shaft pulley, a separate resilient drivingbelt connecting each of the paired and aligned pulleys and sheaves, acrank shaft journaled in the stationary table, perpendicular to thelower face thereof and including a worm gear engaged with the wormshaft, a first crank arm mounted on said crank shaft below thestationary table and rotatable with the crank shaft, a second crank armpivotally mounted on the under side of the stationary table and spacedfrom said first crank arm, a first connecting rod pivotally connected atone end to the second crank arm proximate its pivot point and at theother end to the first crank arm, and a second connecting rod pivotallyconnected at one end to the sub-table and at the other end to the secondcrank arm at the free end thereof, said, several connecting rods actingto reciprocate the sub-table 4. An auxiliary compound grinder of thetype defined in claim 2, and further distinguished by the first crankarm being cylindrical in shape with a diametrical dovetail slot cut inthe lower face thereof, a pivot block, adapted to engage the end of thefirst connecting rod, slidably mounted in said slot, and threaded meanson said crank arm engaged with said pivot block and adapted to move samelongitudinally of the slot, between adjusted positions, with referenceto the center of rotation of the 10 first crank arm.

References Cited in the file of this patent UNITED STATES PATENTS2,821,815 Banko Feb. 4, 19 58

